Matt Fitzgerald—The average health-conscious American is a little confused about what constitutes an optimal diet. One source of confusion is the tremendous volume of nutrition information to which we are exposed. It so saturates our culture that even those who avoid reading nutrition books and magazine articles get plenty of it. For example, just yesterday at the grocery store I grabbed a watermelon from a large crate that had a full paragraph about the merits of lycopene (a nutrient with highly touted antioxidant properties) printed on its side.
Those who conscientiously try to heed the news of each new “miracle nutrient” that’s identified and every other sort of nutrition discovery that comes along can easily become overwhelmed. I imagine my fellow shoppers wandering through the supermarket aisles thinking, “Let’s see, to prevent liver cancer I need carotenoids, which are in carrots; and to balance my prostaglandins I need alpha-linolenic acid, which is in salmon; and to lower my cholesterol I need plant sterols, which are in – dammit, I can’t remember!” No one can retain it all, and the quantities of information we do retain are overwhelming enough to make shopping, planning meals, and eating a far more enervating set of activities than they should be.
A second source of confusion is the fact that so much of the nutrition information we get is contradictory. Why can’t the nutrition authorities keep their story straight? There’s a host of reasons. In the following pages, we’ll look at some of them.
Human Nutrition is Complex
There’s just no getting around the fact that human nutrition is a breathtakingly complex subject. There are tens of thousands of biologically active chemicals at work in the human body, and almost all of them are derived from food in one way or another. Scientists are only able to study one or two small pieces of the intricate puzzle of human metabolism at a time. All too often, they are unable to observe how these pieces are affected by other, unseen pieces, and as a result they draw conclusions that will have to be retracted or revised when these other pieces come into view. Good scientists understand that all of their conclusions are tentative and subject to later revision, but we often have little choice but to base our dietary decisions on the tentative conclusions of nutrition scientists, and it can be frustrating when they are in fact changed.
One example of this dynamic is the story of margarine. Scientists and doctors advocated margarine as a healthier alternative to butter in the 1960s because margarine is lower in saturated fats than butter, and a link between saturated fat and heart disease had been recently discovered. What these doctors and scientists did not know at the time is that trans fats, of which margarine is full, are far worse. The advice to replace butter with margarine has since been retracted.
Scientists Make Mistakes, Too
While nutrition science in general can’t be blamed for its piecemeal progress, individual nutrition scientists frequently commit avoidable errors that only increase our confusion once they are exposed. More often than you might think, poorly designed nutrition studies and poorly interpreted data yield false conclusions that must be corrected later. Common problems include small sample sizes, faulty data collection methods, lack of adequate placebo controls, and dismissal of unexpected results.
In some cases, studies are designed or interpreted badly with full awareness of the researchers, because they want to please the party (often a food industry corporation) funding the study. In other cases, researchers are so keen on seeing their pet hypothesis validated that, well, they make it right. An example of this latter scenario comes from a large, international study that sought a correlation between cholesterol levels and heart disease in 27 countries. According to the raw data there was only a weak correlation, but inexplicably, in their analysis of this data, the researchers leading the study simply threw out data from countries that defied their expectations and found a much stronger correlation in the remaining data. Years later the correlation between total blood cholesterol levels and heart disease was proven to be much weaker than we were once led to believe.
Blame the Media
The popular media, aware of the huge public appetite (so to speak) for nutrition information, and moving, as they do, much faster than science, frequently overhype individual studies, and thus make it seem as though the scientific understanding of the right way to eat is changing more rapidly than it actually is. Several years ago, you may recall, the media were touting soy as the ultimate superfood; a few years later, inevitably, they were hyping the dangers of eating too much soy. But if you had read only the studies on which these stories were based, you would have seen nothing like this dramatic reversal.
Anyone Can Give Nutrition Advice
A large fraction of the men and women who are given the status of nutrition experts in our society are actually nothing of the sort. Much of the dietary advice proffered by these poseurs is either repeated myth or made up completely. Bill Philips, author of the zillion-selling Body for Life, is a good example of a nutrition expert by reputation only. Among the pearls of wisdom dispensed in his book is the advice not to eat anything within an hour of completing a workout. I don’t know where Philips got this idea, but it is one of the gravest nutrition mistakes an athlete could make.
We have no one but ourselves to blame when we accept the likes of sitcom actress-turned-cottage industry of one Suzanne Somers, putative author of Suzanne Somers’ Get Skinny on Fabulous Food, as our nutrition oracles. But some of the fake nutrition experts are less easy to spot. For example, you might be surprised to learn that medical students typically get very little nutrition education in their four-year curriculum, yet they routinely give nutritional guidance to patients once they begin practicing. Because they did not get their knowledge of nutrition in their formal training, they get it all too often from the same place we do: the diet section of the bookstore.
Nutrition Beliefs are Often Based on Ideology
The large gaps in our scientific knowledge of human nutrition have left many an opening for ideologists of various stripes to peddle dietary philosophies based as much on politics and emotion as on fact. The immense cultural importance of food makes these philosophies very seductive to their peddlers and consumers alike. There are primitivists who contend that one should eat only raw plant foods, conspiracy theorists who view all processed foods as poisonous, food industry toadies who insist that the best foods are engineered, contrarians who are all too ready to subvert the conventional nutritional wisdom, classic conservatives who will go to any lengths to defend the majority opinion against all evidence, and other types. There will come a day when our growing scientific knowledge of human nutrition squeezes out most of the ideologists, but we’re not there yet.
Sometimes Greed Comes Before Honesty
There is a lot of money to be made in selling nutrition advice and products that are based on particular kinds of nutrition advice, and sometimes there’s even more money to be made when the advice is grounded in partial or complete falsehoods. The ultimate example is Robert Atkins, who almost single-handedly spawned a low-carb diet industry that peaked at $15 billion a year based on a largely bogus dietary philosophy.
It’s important to understand that profit motives also color what is presented to us as nutritional fact in more insidious ways. University nutrition departments now depend heavily on large food and drug companies to fund research. (I’ve interviewed veteran researchers who remember when it was unthinkable to accept funding from such sources.) Even when these relationships don’t affect the results of research, they affect the types of studies that are done, and are not done. Studies designed to prove that a certain product solves a health or nutrition problem are much more likely to be funded than studies that merely serve to increase our knowledge of human nutrition.
We want a magic bullet.
The fake experts and profit seekers couldn’t take advantage of the public so easily if not for the magic bullet-seeking mentality of the average consumer. We want to hear that there is a simple, instant, and easy dietary solution to our health and weight issues. We want the ultimate revolutionary breakthrough diet secret. Given a choice between a fake expert telling us what we want to hear and a real one giving us the same old truth, all too often we will choose to listen to the fraud. But doing so will not bring the promised results, so our sense of confusion escalates.
It is by no means wrong to want simple nutrition guidelines. In fact, nutrition guidelines have to be simple if we are to benefit from them. However, they also have to be realistic. Many of the fake experts steer us wrong by oversimplifying the actual phenomenon of human nutrition. Atkins blamed everything on carbohydrates. Peter D’Adamo reduced it all to a simple game of matching nutrition to blood type. Such diets are very simple, but their simplicity avails nothing because it derives from false ideas about nutrition. The right way to generate simple guidelines for eating is to step back from the level of specific do’s and don’ts to the level of general principles. While the phenomenon of human nutrition is irreducibly complex, the core principles of healthy eating are not. By learning and focusing on the latter, you can make good nutrition choices consistently without getting bogged down in too many details.
About the Author:
Matt Fitzgerald is the author of Racing Weight (VeloPress, 2009).